43 lines
809 B
Go
43 lines
809 B
Go
package web
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import "sync"
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// Broadcaster fans a string message out to all SSE subscribers. Slow
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// subscribers drop messages rather than blocking publishers.
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type Broadcaster struct {
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mu sync.Mutex
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subs map[chan string]struct{}
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}
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func NewBroadcaster() *Broadcaster {
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return &Broadcaster{subs: make(map[chan string]struct{})}
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}
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func (b *Broadcaster) Subscribe() chan string {
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ch := make(chan string, 8)
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b.mu.Lock()
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b.subs[ch] = struct{}{}
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b.mu.Unlock()
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return ch
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}
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func (b *Broadcaster) Unsubscribe(ch chan string) {
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b.mu.Lock()
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if _, ok := b.subs[ch]; ok {
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delete(b.subs, ch)
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close(ch)
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}
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b.mu.Unlock()
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}
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func (b *Broadcaster) Publish(msg string) {
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b.mu.Lock()
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defer b.mu.Unlock()
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for ch := range b.subs {
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select {
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case ch <- msg:
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default: // drop for slow subscriber
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}
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}
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}
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